Design of a ready-made prefab concrete vaulted floor element

Article by : Merel Bosch
Supervisors : Arjan Habraken

The construction industry faces pressure to reduce its environmental impact. By lowering material use in the construction sector, embodied carbon emissions can be reduced. This project investigates the design of a ready-made prefabricated concrete vaulted floor element that transfers loads primarily through compression. The element is horizontally restrained by steel tension ties and is intended to be installed without the need for scaffolding. By optimising the structural form and enabling efficient prefabrication, the proposed system aims to significantly reduce material consumption compared to conventional concrete floors, while allowing rapid on-site assembly and reducing the risk of construction inaccuracies and errors.

Conventional floor elements rely on bending, while a shell element transfers loads through compression
Block research group – ETH Zurich
Reference project that assembles prefabricated elements on site
Design

The main part of the design is a shell measuring approximately 3 by 6 meters. Local height variations are added to ensure that the line of thrust remains within the material cross-section, even under asymmetrical and point loads. To transfer loads efficiently towards the four corner supports, topology optimisation is applied. Karamba 3D in Grasshopper is used to identify the principal stress lines, which define the rib pattern. Based on this pattern, a shell is generated through form-finding using the RhinoVAULT plugin.

Topology optimisation rib pattern
Form finding in RhinoVAULT using the Thrust Network Analysis

After all elements are combined into a single model, a structural analysis is carried out in Abaqus to determine the required thicknesses of the shell and ribs. Finally, the production of the element is considered, and a scale model of the final element may be produced.

References

Rippmann Floor System (RFS)®. (2023). VAULTED AG. https://www.vaulted-floors.com/system

Mata-Falcón, J., Bischof, P., Huber, T., Anton, A., Burger, J., Ranaudo, F., Jipa, A., Gebhard, L., Reiter, L., Lloret-Fritschi, E., Van Mele, T., Block, P., Gramazio, F., Kohler, M., Dillenburger, B., Wangler, T., & Kaufmann, W. (2022). Digitally fabricated ribbed concrete floor slabs: a sustainable solution for construction. RILEM Technical Letters, 7, 68–78.